Heavy metals alter the electrokinetic properties of bacteria, yeasts, and clay minerals

Collins, Y E; Stotzky, G.

doi:10.1128/aem.58.5.1592-1600.1992

Cited by 128 publications

(36 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…With a further rise in pH, uranium sorption by lyophilized biomass showed a sharp decline, while the living counterpart seemed less affected. The observed trend with regard to pH (ie low uranium uptake by bacterial biomass increasing with pH from acidic to near neutral conditions) may be explained by (i) the high solubility of uranyl ions and competition by H + for uranium binding sites in the acidic conditions,3 (ii) increasing binding affinity by the biomass of monovalent uranyl species (UO 2 OH + , (UO 2 ) 3 (OH) 5 + ) formed at higher pH (pH 4.0–5.0) over the divalent (UO 2 2+ ) at low pH (pH 2.0)26 and (iii) decrease in dissolved uranyl ion concentration at higher pH due to the formation of solid schoepite (4UO 3 9H 2 O) reducing uranium sorption 9. 27 Such a trend has also been observed previously in P aeruginosa CSU,3 Rhizopus arrhizus, Streptomyces levoris 28 and S longwoodensis ,29 suggesting a redox range between pH 4.0 and 5.0 for maximum uranium sorption 3.…”

Section: Resultsmentioning

confidence: 99%

Biosorptive uranium uptake by a Pseudomonas strain: characterization and equilibrium studies

Sar

D’Souza

2001

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

The biosorptive uranium(VI) uptake capacity of live and lyophilized Pseudomonas cells was characterized in terms of equilibrium metal loading, effect of solution pH and possible interference by selected co-ions. Uranium binding by the test biomass was rapid, achieving >90% sorption ef®ciency within 10 min of contact and the equilibrium was attained after 1 h. pH-dependent uranium sorption was observed for both biomass types with the maximum being at pH 5.0. Metal uptake by live cells was not affected by culture age and the presence of an energy source or metabolic inhibitor. Sorption isotherm studies at a solution pH of either 3.5 or 5.0 indicated ef®cient and exceptionally high uranium loading by the test biomass, particularly at the higher pH level. At equilibrium, the lyophilized Pseudomonas exhibited a metal loading of 541 AE 34.21 mg g À1 compared with a lower value by the live organisms (410 AE 25.93 mg g À1 ). Experimental sorption data showing conformity to both Freundlich and Langmuir isotherm models indicate monolayered uranium binding by the test biomass. In bimetallic combinations a signi®cant interference in uranium loading was offered by cations such as thorium(IV), iron(II and III), aluminium(III) and copper(II), while the anions tested, except carbonate, were ineffective. Uranium sorption studies in the presence of a range of Fe 3 and SO 4 2Àconcentrations indicate a strong inhibition (80%) by the former at an equimolar ratio while more than 70% adsorption ef®ciency was retained even at a high sulfate level (30 000 mg dm À3). Overall data indicate the suitability of the Pseudomonas sp biomass in developing a biosorbent for uranium removal from aqueous waste streams.

show abstract

Section: Resultsmentioning

confidence: 99%

Biosorptive uranium uptake by a Pseudomonas strain: characterization and equilibrium studies

Sar

D’Souza

2001

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

show abstract

“…2). Solution pH strongly in£uences the characteristics of the cell envelope [10,28,29] and metal chemistry [1]. Changes in both these tend to alter metal binding at bacterial surfaces [10,30,31].…”

Section: Discussionmentioning

confidence: 99%

The impact of surface attachment on cadmium accumulation by Pseudomonas fluorescens H2

McEldowney

2000

FEMS Microbiology Ecology

View full text Add to dashboard Cite

Cadmium accumulation by Pseudomonas fluorescens H2 attached to glass surfaces and by cells free in suspension in maleate buffer was compared and showed several major differences. The time to saturation of cells with Cd(2+) was different for attached and free cells, although both showed biphasic uptake of Cd(2+). The accumulation of Cd(2+) by free cells was inhibited by the presence of zinc but remained several orders of magnitude higher than accumulation by attached cells. The presence of Zn(2+), however, did not inhibit Cd(2+) uptake by cells attached to the solid substratum. Cadmium uptake still increased with Cd(2+) concentration for both free and attached cells in the presence of Zn(2+). The accumulation of Cd(2+) by both free and attached cells increased with pH up to pH 11. The presence of a metabolic inhibitor, carbomyl cyanide m-chlorophenyl-hydrazone, reduced the uptake of Cd(2+) by free cells by 40% but reduced uptake by attached cells by only 25%. Approximately 65% of Cd(2+) accumulated by cells free in suspension was associated with the cell wall, 33% was present in the cytoplasm and only 2% was bound to exopolymer. The results suggest that the characteristics of heavy metal accumulation by bacterial cells are substantially affected by attachment to solid surfaces.

show abstract

“…The adsorptive interactions between particles of the same charge have frequently been considered in terms of the Derjaguin-Landau-Verwey-Overbeck (DLVO) theory of colloid stability (24). Although the DLVO theory has been applied to (5,14,17,29,30), numerous complications arise because cells are not nonpermeable objects of well-defined structure and surface topography. One must know the value of the surface potential to calculate the electrostatic repulsion forces.…”

Section: And Discussionmentioning

confidence: 99%

Solubilization of Minerals by Bacteria: Electrophoretic Mobility of Thiobacillus ferrooxidans in the Presence of Iron, Pyrite, and Sulfur

Blake

Shute

Howard

1994

Appl Environ Microbiol

View full text Add to dashboard Cite

ThiobaciUus ferrooxidans is an obligate acidophile that respires aerobically on pyrite, elemental sulfur, or soluble ferrous ions. The electrophoretic mobility of the bacterium was determined by laser Doppler velocimetry under physiological conditions. When grown on pyrite or ferrous ions, washed cells were negatively charged at pH 2.0. The density of the negative charge depended on whether the conjugate base was sulfate, perchlorate, chloride, or nitrate. The addition of ferric ions shifted the net charge on the surface asymptotically to a positive value. When grown on elemental sulfur, washed cells were close to their isoelectric point at pH 2.0. Both pyrite and colloidal sulfur were negatively charged under the same conditions. The electrical double layer

show abstract

Heavy metals alter the electrokinetic properties of bacteria, yeasts, and clay minerals

Cited by 128 publications

References 35 publications

Biosorptive uranium uptake by a Pseudomonas strain: characterization and equilibrium studies

Biosorptive uranium uptake by a Pseudomonas strain: characterization and equilibrium studies

The impact of surface attachment on cadmium accumulation by Pseudomonas fluorescens H2

Solubilization of Minerals by Bacteria: Electrophoretic Mobility of Thiobacillus ferrooxidans in the Presence of Iron, Pyrite, and Sulfur

Contact Info

Product

Resources

About